Properties of Si3N4 Ceramics Sintered in Air and Nitrogen Atmosphere Furnaces

Abstract

Mass loss and mechanical properties including density and morphology of Si 3 N 4 ceramics sintered in air and in N 2 atmospheres were comparatively studied. The trends of mass loss with increasing temperature of the Si 3 N 4 sintered in air and in N 2 atmospheres were significantly different. The densities of the specimens sintered at the same temperature both in air and in N 2 atmospheres were similar. However, the mechanical properties of the materials sintered in air were lower than those sintered in N 2 atmosphere. Vickers hardness H V , fracture toughness K IC and biaxial flexure strength of the specimens sintered in air and in N 2 atmospheres were 12.7 GPa, 5.5 MPaெm 12 and 263 MPa, and 13.3-13.5 GPa, 6.0-6.8 MPaெm 12 and 340-406 MPa, respectively.

Low‐Cost Silicon Nitride from β‐Silicon Nitride Powder and by Low‐Temperature Sintering

“…On the other hand, the cost of β powder is usually lower than that of α powder with similar purity and grain size. In addition, some papers have suggested that β powder has better sinterability than α powder . However, these reports did not measure the differences between α and β powders in detail, especially at temperatures below 1700°C.…”

“…In addition, some papers have suggested that b powder has better sinterability than a powder. 4,7,8 However, these reports did not measure the differences between a and b powders in detail, especially at temperatures below 1700°C. If b powder has better sinterability than a powder at lower temperatures around 1600°C and the sintered body has acceptable mechanical properties, the use of b powder would be a potential way to reduce the production cost.…”